The news: A California patrol officer brutally punching a black woman in the head repeatedly was caught on video. Shot on Tuesday on Interstate 10 near La Brea Ave, the video shows the woman moving away from the officer before being tackled and beat down.

According to David Diaz, who shot the video, it looked like the policeman delivered at least 15 punches to the head. What's absolutely clear is that there is no plausible excuse for the amount of violence directed at the woman, who appears to have been beaten into submission with no regard for her health or safety.

The California Highway Patrol says it was aware of the incident and had initiated a standard investigation concerning the use of force. On Friday, CHP Assistant Chief Chris O'Quinn released more information about the incident: All this, apparently, was because the woman was endangering herself by walking down the wrong side of the freeway. Since the woman is undergoing psychiatric evaluation, the possibility remains that the woman was mentally ill.

Quinn said that civilians who are "not accustomed to the speed and conditions" of the roadway could not grasp the urgency of the situation. "The most dangerous thing that we face is traffic," he added.

Community activist Earl Hutchinson demanded a federal investigation. "Subduing is one thing if you're going to make a lawful arrest. There’s no question about that. You have the authority to do that," he said. "But a punch and a beating? I’m sorry, you’ve crossed the line." Other activists were shocked, saying CHP typically has had a good track record on community relations and racial profiling. Pedro Baez said that, "We saw something that was just repulsive, reprehensible and totally out of character for them."

The background: The outcome of this case has yet to play out, but violent encounters between police and the mentally ill are sadly common in America. Earlier this year, a report from the Treatment Advocacy Center says over 10 times as many mentally ill inmates are languishing in the U.S. prisons as are receiving treatment in hospitals and mental health facilities.

"The lack of treatment for seriously ill inmates is inhumane and should not be allowed in a civilized society," said TAC founder and lead author Dr. E. Fuller Torrey. "This is especially true for individuals who — because of their mental illness — are not aware they are sick and therefore refuse medication."

Because America's mental health system is in shambles and often offers little to no preventative care, officers who aren't well-trained on how to handle the mentally ill often respond with unnecessary or counterproductive force. In 2013, TAC discovered that at least 50% of lethal shootings by officers involved a mentally ill suspect. And the Orlando Sentinelfound between 1999 and 2002 in central Florida, of 428 reported police killings, 30 followed after family members called to report a suicidal person.